走滑断层和逆断层位错作用下地铁隧道损伤特征对比分析

隧道作为重要的轨道交通工程，近年来在地震中受到了不同程度的破坏，特别是跨断层的隧道，其抗震性能越来越受到人们的关注。为了能够更好地评价隧道的整体损伤情况及把握其损伤特征，以北京地铁7号线为研究对象，利用有限元软件ABAQUS建立模型，采用拟静力法，以隧道直径变化率作为损伤指标分析了隧道在走滑断层以及逆断层位错作用下的损伤特征，对比了两种断层位错作用下损伤状态与地震强度之间的关系、损伤范围和位置以及损伤程度。结果表明:跨断层隧道在断层错动作用下损伤只发生在断层带附近；当震级处于6.0～8.0级时，隧道衬砌损伤程度随震级的增大而增大；在覆土厚度相同的条件下，同震级时逆断层位错作用下隧道损伤程度要比走滑断层作用下大得多；走滑断层位错作用下隧道结构损伤主要发生在拱腰处，逆断层位错作用下主要发生在拱肩－拱脚以及拱顶－拱底处。

Comparative analysis of damage characteristics of subway tunnels under strike-slip fault and reverse fault dislocation

As an important rail transit project,tunnels had been damaged in earthquakes to varying degrees in recent years,especially tunnels across faults,whose seismic performance had attracted increasing attention. In order to better evaluate the overall damage of the tunnels and study their damage characteristics,a finite element model of Beijing Metro Line 7 was established to analyzes the damage of the tunnel under strike-slip fault and reverse fault dislocation,using the pseudo-static method with the tunnel diameter variety rate as the damage index. The relationship between the damage state and the seismic intensity,the damage extent and location,and the degree of damage under the two fault dislocations were compared. The results show that the damage of the cross-fault tunnel under fault dislocation only occurs near the fault zone. When the earthquake magnitude is 6.0~8.0,tunnel lining damage develops with the increase of the magnitude. Under the same cover thickness,the degree of tunnel damage under reverse fault dislocation is much greater than that under strike-slip fault at the same earthquake magnitude. The damage of the tunnel structure under strike-slip fault dislocation mainly occurs at the arch waist,while that under reverse fault dislocation mainly occurs at the shoulder and foot of arch and the top and bottom of arch.